Coats Terko Satin is a cotton wrapped polyester corespun thread with a glace finish. This thread combines the excellent sewing performance of cotton with the superior strength and elongation characteristics of continuous filament polyester. The cotton wrap protects the polyester core from needle heat even in the most demanding of applications. The glace finish binds together the fibrous surface of the thread and creates a lustrous finish with enhanced abrasion resistance. In wet, outdoor conditions the cotton wrap absorbs water and swells to fill the needle holes to prevent leakage.